Drive unit of a laundry machine and laundry machine having the same, and a controlling method of the laundry machine

ABSTRACT

The present disclosure relates to a twin laundry machine, more particularly, to a twin laundry machine configured to control mutual motor operations of one or more laundry machines provided therein not to be overlapped with each other, in case the one or more laundry machines are put into operation to perform washing. The present disclosure also relates to a twin laundry machine of which a motor for driving a drum has an improved heat radiation function, more particularly, to a twin laundry machine which includes a sub-washing machine with a smaller size than a normal washing machine and frequent exposure to high temperature usage environments.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/628,483, filed on Jun. 20, 2017, which is a continuation of U.S.application Ser. No. 15/416,106, filed on Jan. 26, 2017, which claimsthe benefit of earlier filing date and right of priority to KoreanApplications Nos. 10-2016-0010017, 10-2016-0175181, and 10-2016-0181567,filed on Jan. 27, 2016, Dec. 20, 2016, and Dec. 28, 2016, respectively,in Korea, the entire contents of which are hereby incorporated byreference herein in their entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

Embodiments of the present disclosure relate to a twin laundry machine,more particularly, to a twin laundry machine configured to controlmutual motor operations of one or more laundry machines provided thereinnot to be overlapped with each other, in case the one or more laundrymachines are put into operation to perform washing.

Embodiments of the present disclosure also relate to a twin laundrymachine of which a motor for driving a drum has an improved heatradiation function, more particularly, to a twin laundry machine whichincludes a sub-washing machine with a smaller size than a normal washingmachine and frequent exposure to high temperature usage environments.

Embodiments of the present disclosure also relate to a drive unit of alaundry machine which is capable of improving the function ofheat-radiation performed by a drive for driving a drum, and a laundrymachine having the same.

Discussion of the Related Art

A conventional laundry machine is used in treating laundry or washingobjects through diverse operations combined with washing, spinningand/or drying cycles.

Such a conventional laundry machine includes a washing machineconfigured to wash laundry such as clothes and beddings by using theemulsification activity of detergent, the water current activitygenerated by the rotation of a tub or pulsator and the mechanical powerapplied by the pulsator; a dryer configured to dry laundry by applyinghot air or cold air to the laundry; and a refresher configured to removewrinkles from clothes by applying steam. Also, there are diverse typesof laundry machines configured to provide diverse functions such as awashing machine having a washing function and a drying function.

The conventional laundry machine has to be provided with the minimumamount of wash water needed to perform washing. If a large volume of atub is provided, unnecessarily much wash water has to be provided evenin washing a small amount of laundry.

To solve such a disadvantage of water waste, a mini-washing machine or awashing machine for infants has been provided.

However, it causes a spatial disadvantage to install both oneconventional laundry machine and one mini-washing machine together so asto use both of them. It also causes a design disadvantage to use theconventional laundry machine and the mini-washing machine which havedifferent designs and versions.

Recently, a twin laundry machine including two washing machines isprovided to address the problem. The twin laundry machine is provided asone body with two units (or two washing machines). Specifically, a firstwashing unit and a second washing unit are installed as if having onebody so as to make better use of a space and improve use convenience andprovide an effectively beautiful design.

The first washing unit provided in the twin laundry machine may be amain-washing machine with a relatively large size and the second washingunit may be a sub-washing machine or a mini-washing machine with arelatively small size. The volume of the first washing machine forwashing or drying is larger than that of the second washing unit.Accordingly, a user seems to be able to use one of the two washingmachines selectively according to needs and give specific functions toeach of the washing machines. The user can be provided with thespecialized functions that cannot be provided when having one laundrymachine.

Vibration might be caused when the two washing units perform washing atthe same time or two twin laundry machines are put into operation. Inthis instance, the vibration results in errors of the twin laundrymachine and power consumption might drastically rise. The washing unitsare not completely and physically separated from each other and thevibration generated in one of the washing units could directly affectthe other washing unit.

As one usage example of the twin laundry machine, the second washingunit is provided in main consideration of sanitation and it is used intreating infant clothes or underwear. Accordingly, the second washingunit is used a lot in sterilizing laundry in boiling water which isheated to a preset high temperature. A sterilize-washing course takes arelatively long time to simply heat wash water to a preset hightemperature and keep the high temperature after that. In other words,the sterilize-washing course is implemented to perform washing in astate where wash water is kept at a high temperature for a relativelylong time.

To perform the sterilize-washing course, a heater is driven to heat washwater to a preset high temperature. Different from the first washingunit with the normal size, the second washing unit has a relativelysmall size and volume with a tiny internal space. Accordingly, the heatgenerated while the wash water is heated to the preset high temperatureseems to be transferred to the other components which are providednearby.

Especially, the high-temperature heat happens to affect the drive unitconfigured to drive the second washing unit. For example, thehigh-temperature heat might be transferred to a motor for driving a drumprovided in the second washing unit.

The motor generates heat by its own driving. If exposed to a preset hightemperature or more, the motor fails to drive normally and happens todamage or stop its drive unexpectedly. Especially, it is quite importantto keep a stator which generates much heat out of overheat.

FIG. 1 illustrates a schematic diagram of a rotor provided in a motor ofthe conventional laundry and FIG. 2 is a sectional diagram illustratingan air inlet part shown in FIG. 1 along a circumferential direction.

A stator of the motor may be coupled to an outer rear wall of a tub, anda drum may be rotatably mounted in a tub.

As shown in FIG. 1, the rotor 10 includes a rotor frame 20 and aplurality of magnets 60. The rotor frame 20 includes a side wall 30 towhich the plurality of the magnets 60 are mounted; and a bottom wall 40.

A central portion of the bottom wall 40 is connected to a shaft of thedrum. When the rotor is rotated by the electromagnetic force generatedbetween the stator and the rotor, the rotational force of the rotor istransferred to the drum shaft and the drum.

On a FIG. 1 basis, the side wall 30 is vertically extended upward fromthe bottom wall 40. In other words, the side wall 30 is extended from aradial-direction end of the circular bottom wall.

The shape of the side wall 30 and the bottom wall 40 allows the rotorframe 20 to have a container-shaped appearance so as to define aninternal space. The stator is disposed in the internal space of therotor frame 20.

It is well known that the stator is coupled to the tub through thecentral portion of the tub and a coil is provided distant from a centerof the stator in a radial direction. Corresponding to the stator, an airinlet part 41 is provided. In other words, the air inlet part 41 isprovided in the bottom wall 40 and a plurality of air inlet parts 41 maybe provided along a circumferential direction. A plurality of openings43 may be defined.

A hub 50 is formed in the central portion of the bottom wall 40 and aconnector may be coupled to the hub 50. The connector may be connectedto the drum shaft.

An embossing portion 44 may be formed in the bottom wall 40. In thisinstance, a plurality of embossing portions 44 may be provided along acircumferential direction. The embossing portions 44 and the air inletparts 41 may be arranged alternatively.

The embossing portions 44 may be provided to reinforce the stiffness ofthe rotor frame 20, especially, the bottom wall 40. The bottom wall 40is formed as a thin plate so that distortion or floppiness might begenerated in the bottom wall 40 during the rotation of the rotor 10. Tominimize such distortion or floppiness, the embossing portions 44 may beprovided.

The air inlet parts 41 may be provided to suck external air, in otherwords, cold air into the rotor. On a FIG. 2 basis, the air inlet parts41 may be provided to suck air upward from a lower portion of the rotor.

When the rotor 10 is rotated, air flux may be generated in the internalspace of the rotor (in other words, the space where the stator isprovided) by a blade 42 and the pressure inside the rotor is relativelylower than the pressure outside the rotor. In addition, the air heatedby the stator tends to go up.

Accordingly, when the rotor 10 is rotated, external cold air is suckedinto the stator via the air inlet parts 41 and hot air inside the statorgoes up and outside via a gap between the stator and the rotor or thespace between the stator and the tub.

The rotor having the structure of the air inlet parts 41 has no bigproblem chilling the stator.

Different from the conventional motor, the motor for driving the secondwashing unit could be exposed not only to the heat generated therein,especially, the stator but also the heat transferred from the hot tubarranged nearby. Accordingly, such the heat has to be radiatedeffectively enough to keep the driving of the drum.

However, the rotor having the structure of the conventional air inletparts 41 only chills the heat generated in the stator but fails toprovide a satisfactory cooling function if the heat transferred from thehot tub is added.

That is because the holes for sucking external air into the rotor arealigned or parallel with the rotational direction of the rotor. In otherwords, external air cannot be sucked into the rotor smoothly.

Moreover, the blade is extended near the holes toward the stator anddisposed in the rotor so that it directly blows internal air of therotor, not external air. As the blade blows relatively-high-temperatureair toward the stator, not external air, the cooling efficiency maybecome lower.

It may be considered to enhance the cooling efficiency that the blade 42is formed higher. However, such the blade stands high toward the statorand it is limited to increase the height of the blade. If the bladebecomes higher, the rotor also has to become higher. Accordingly, it isalso limited because of the small installation space and the relativelysmall size.

It is necessary to invent and provide a motor which is capable ofeffectively and efficiently radiating not only the heat generated in thestator but also the heat transferred from a surrounding high-temperatureenvironment and a drive unit including such a motor which is provided ina laundry machine.

It is also necessary to invent and provide a second washing unit whichhas an improved reliability by effective radiating of the heat generatedin a drive unit of the second washing unit and a twin laundry machinehaving such a second washing unit.

Moreover, it is necessary to invent and provide a twin laundry machinewhich has the improved reliability and durability of first and secondwashing units by minimizing of the influence of the heat generated in adrive unit of the second washing unit on the first washing unit.

SUMMARY OF THE DISCLOSURE

An object of the present disclosure is to overcome the disadvantages ofthe conventional laundry machine and the conventional twin laundrymachine noted above.

Embodiments of the present disclosure provide a twin laundry machineincluding a plurality of washing units configured to perform washingindependently, the twin laundry machine configured to set operations ofmotors provided in the washing units, respectively, not to be overlappedwith each other, when the washing units perform washing at the sametime, and a control method of the same.

Embodiments of the present disclosure also provide a laundry machine anda twin laundry machine which are capable of chilling a drive unitprovided in each of the machines for driving a drum effectively and moreefficiently.

Embodiments of the present disclosure also provide a twin laundrymachine which is capable of chilling a drive unit provided in asmall-sized second washing unit thereof more effectively andefficiently.

Embodiments of the present disclosure also provide a laundry machine anda twin laundry machine which are capable of chilling a drive unitprovided in each of the machines, especially, a stator of a motoreffectively.

Embodiments of the present disclosure also provide a laundry machine anda twin laundry machine which can be realized by changing a conventionalstructure of a rotor, even without installing or mounting an auxiliarycomponent for chilling.

Embodiments of the present disclosure also provide a rotor having astructural stiffness and capable of enhancing chilling efficiency byintegral forming of an air inlet structure and an embossing structure asone structure, and a laundry machine or twin laundry machine includingthe same.

Embodiments of the present disclosure also provide a drive unit having anoticeably improved heat-radiation function and a laundry machineincluding the same.

Embodiments of the present disclosure also provide a control method of atwin laundry machine comprising a first washing unit comprising a firsttub and a first motor for driving the first tub; a second washing unitcomprising a second tub and a second motor for driving the second tub,the second washing unit separately operable from the first washing unit;a first controller for controlling the first washing unit; and a secondcontroller for controlling the second washing unit, wherein the firstcontroller categorizes operations of the first motor for performingwashing, rinsing and spinning cycles according to operation settings bymotion unit, and sets the time period in which the first motor performsone motion one time as one operation-on period and controls anoperation-on period of the first motor and an operation-on period of thesecond motor not to be overlapped with each other.

Embodiments of the present disclosure also provide a control method of atwin laundry machine comprising a first washing unit comprising a firsttub and a first motor for driving the first tub; a second washing unitcomprising a second tub and a second motor for driving the second tub,the control method comprising: a step for controlling the first motor toperform a first motion of the motions implemented to give the laundryloaded in the first tub certain washing effects for a first operation-onperiod; a step for controlling the second motor to standby for a firstoperation-off, corresponding to the first operation-on period; a stepfor controlling the second motor to perform a second motion of themotions for a second operation-on period, when the first operation-onperiod ends; a step for controlling the first motor to standby for asecond operation-off period, corresponding to the second operation-onperiod; and a step for controlling the first motor and the second motorto perform the motions combined with the plurality of the operations foroperation-on periods which are set not to be overlapped with each other,respectively.

In the twin laundry machine according to the embodiments, the motor fordriving the drum, specifically, the stator according to embodimentswhich will be described later may be applied. Especially, the stator fordriving the drum provided in the second washing unit which has a highfrequency of high-temperature usage environments and a relatively smallsize may be a stator according to embodiments.

To settle the objects of the present disclosure, the drive unit of thewashing unit may include a stator and a rotor. When the rotor isrotated, a new structure of the rotor for sucking a much amount ofrelatively-low-temperature external air may be provided.

To increase the inlet amount of external air, the drive unit of thesecond washing unit includes a stator and a rotor. An external airsupply channel configured to collect external air flow may be formed inan outer bottom surface of the rotor, when the rotor formed in an arcdirection is rotated.

An opening may be formed near the external air supply channel andvertically formed in the bottom surface of the rotor, to communicatewith an internal space of the rotor.

The drive unit of the second washing unit may include a stator and arotor in accordance with another embodiment of the present disclosure.An opening may be vertically formed

Embodiments of the present disclosure also provide a twin laundrymachine comprising: a first washing unit comprising a first tub, a firstdrum and a first drive unit for driving the first drum; a second washingunit comprising a second tub, a second drum and a second drive unit fordriving the second drum, wherein the second drum has a diameter which islarger than the height and a rotation axis which intersects a rotationaxis of the first drum, the second drive unit comprises a stator fixedto an outer surface of a bottom wall of the second tub; a drum shaftconnected to the second drum, penetrating the second tub; and a rotorcoupled to the drum shaft and rotatably surrounding the stator, and therotor comprises a rotor frame; a magnet; and a connector for connectingthe rotor frame and the drum shaft with each other, and the rotor framecomprises a side wall in which the magnet is mounted; a bottom wallhorizontally extended from a lower end of the side wall; and an airinlet part formed in the bottom wall, and the air inlet part comprises afirst wall projected toward the stator and formed in a circumferentialdirection to face a side wall of the rotor; a second wall projectedtoward the stator from an inner portion of the rotor side wall in aradial direction with respect to the first wall side wall of the rotorand alternate with the first wall in a circumferential direction; athird wall projected in a circumferential direction from an innerportion of the rotor side wall in a radial direction with respect to thesecond wall to face the third wall and the second wall; and a pluralityof side walls for connecting the first wall and the second wall witheach other, and the side wall comprises a first side wall for connectingone end of the first wall and one end of the neighboring second wallwith each other; and a second side wall for connecting the other end ofthe first wall and one end of the neighboring second wall, and anopening in which air is sucked into the rotor frame is formed in thefirst side wall.

The second washing unit may be separable from the first washing unit.

The second tub and the second drum may be vertically arranged in thesecond washing unit.

The second washing unit may be arranged on a top of the first washingmachine.

The rotor may comprise a hub projected from a center of the bottom walltoward the drum shaft and comprising a horizontal surface opposite tothe stator and a vertical surface opposite to the drum shaft.

The connector may be made of a plastic material and coupled to the drumshaft to be coupled to the rotor frame, in close contact with thehorizontal surface and the vertical surface of the hub.

The hub may comprise another vertical surface opposite to the secondwall of the air inlet part and projected toward the stator.

The horizontal surface of the hub may be a bottom wall of the rotor nearthe third wall of the air inlet part.

The second side wall of the air inlet part may form a front side withrespect to a rotational direction of the rotor, and the first side wallin which the opening is formed to suck air may form a rear side withrespect to the rotational direction of the rotor.

An opening formed in a first side wall of the air inlet part may bevertically formed with respect to a bottom surface of the rotor.

A second side wall of the air inlet part may be longer than a first sidewall in which the opening is formed.

One side of the second wall of the air inlet part may be closer to theside wall of the rotor than the other side in a radial direction.

A first side wall of the air inlet part may be connected with one sideof the second wall formed close to the side wall of the rotor in theradial direction.

A predetermined front portion of the second wall of the air inlet partwith respect to the rotation direction of the rotor may be closer to theside wall of the rotor in the radial direction than the other rearportion.

The second wall of the air inlet part may further comprise an opening inwhich air is able to be sucked.

Embodiments of the present disclosure also provide a twin laundrymachine comprising: a first washing unit comprising a first tub, a firstdrum and a first drive unit for driving the first drum; a second washingunit comprising a second tub, a second drum and a second drive unit fordriving the second drum, wherein the second drum has a diameter which islarger than the height and a rotation axis which intersects a rotationaxis of the first drum, the second drive unit comprises a stator fixedto an outer surface of a bottom wall of the second tub; a drum shaftconnected to the second drum, penetrating the second tub; and a rotorcoupled to the drum shaft and rotatably surrounding the stator, and therotor comprises a rotor frame; a magnet; and a connector for connectingthe rotor frame and the drum shaft with each other, and the rotor framecomprises a side wall in which the magnet is mounted; a bottom wallhorizontally extended from a lower end of the side wall; and an airinlet part formed in the bottom wall, and the air inlet part comprisesan external air inlet channel projected from the bottom wall toward thestator and comprising a radial-direction inner wall, a radial-directionouter wall, an upper wall connecting the inner wall and a top of theouter wall with each other, and a front wall connecting the inner walland a front end of the outer wall with each other; and an opening formedby the inner wall, a rear end of the outer wall and the upper wall andthrough which external air is sucked into the rotor frame.

The opening may be vertically formed with respect to a bottom wall ofthe rotor.

The plurality of the air inlet parts may be spaced a preset distanceapart from each other along a circumferential direction.

The circumferential-direction length of the inner wall may be largerthan the circumferential-direction length of the outer wall.

The plurality of the air inlet parts may be consecutively formed along acircumferential direction.

A circumferential-direction gap between the air inlet parts may be equalto or smaller than the circumferential-direction length of the air inletpart.

A circumferential-direction gap between the air inlet parts may belarger than the circumferential-direction length of the air inlet part.

The front wall and the upper wall may form an acute angle.

The front wall and the upper wall may form one inclined wall.

The front wall and the upper wall may be connected with each other by acurved wall.

The opening may be formed by the inner wall, a rear end of the outerwall and a rear end of the upper wall of the neighboring air inlet part.

The air inlet part may further comprise an external air supply channelformed in an inner portion of the external air inlet channel withrespect to a radial direction and projected toward the stator from thebottom wall and formed along the circumferential direction.

The external air supply channel and the external air inlet channel maybe in communication with each other.

The external air supply channel may be consecutively formed along acircumferential direction.

The external air supply channel may comprise an upper wall; an innerwall consecutively formed in an inner radial-direction portion in acircumferential direction; and an outer wall intermittently formed in anouter radial-direction portion in the circumferential direction.

The outer wall of the external air supply channel and the outer wall ofthe external air inlet channel may be alternate with each other along acircumferential direction.

An inner wall of the external air supply channel may be in communicationwith a space between an outer wall of the external air supply channel ina radial direction.

The upper wall of the external air supply channel and an upper wall ofthe external air inlet channel may be connected with each other.

The height of an upper wall of the external air supply channel may beequal to that of the upper wall of the external air inlet channel.

In the embodiments, the first washing unit and the second washing unitprovided in the twin laundry machine are integrally formed with eachother by one body or cabinet.

In the embodiments, the first washing unit and the second washing unitof the twin laundry machine have its independent cabinets, respectively,and the cabinets may be disposed or coupled to each other. Accordingly,the first washing unit and the second washing unit may be provided asindependent washing machines so that it can be said that each of them isa separate independent washing machine.

Embodiments of the present disclosure also provide a drive unit of alaundry machine comprising a tub; a drum mounted in the tub andconfigured to wash laundry; the drive unit connected to a drum shaftpenetrating the tub and configured to drive the drum, the drive unitcomprising a stator fixed to an outer surface of a bottom wall providedin the tub; and a rotor coupled to the drum shaft and supported torotate, with surrounding the stator, wherein the rotor comprises a rotorframe; a magnet; and a connector for connecting the rotor frame and thedrum shaft with each other, and the rotor frame comprises a side wallfor seating the magnet therein; and a bottom wall horizontally extendedfrom a lower end of the side wall, and an external air supply channel isprojected from the stator toward the stator in a circumferentialdirection to be recessed from an outer surface of the bottom wallcontinuously, and the external air supply channel comprises an internalwall formed in a radial direction and an external wall formed in theradial direction; an external wall formed outer to the internal wall ina radial direction; a narrow region having a relatively narrow widthbetween the internal wall and the external wall; and a wide regionhaving a relatively wide width between the internal wall and theexternal wall, and an external air inlet hole is formed an internal orexternal wall portion of the wide region which faces one end of thenarrow region.

The external air supply channel is projected toward the stator andcontinuously extended along a circumferential direction.

The internal wall of the external air supply channel may be continuouslyformed in a circumferential direction and the external wall is bendingin the circumferential direction. Accordingly, the external wall may beformed in a saw-tooth shape or pin-wheel shape.

In contrast, the external wall of the external air supply channel may becontinuously formed in a circumferential direction and the internal wallmay be bent with respect to the circumferential direction. In thisinstance, the internal wall may be formed in a saw-tooth shape orpin-wheel shape.

The external wall comprises a circumferential-direction wall facing theinternal wall in the narrow region and bending in a radial direction tointersect the internal wall in the wide region; and a radial-directionwall bending in a radial direction in the wide region to intersect theinternal wall. The radial-direction wall may be also formed even in thewide region. In this instance, the radius of the radial-direction wallin the narrow is larger than the radius of the radial-direction wall inthe wide region. Because of that, the narrow region is distinguishedfrom the wide region.

The external air inlet hole may be formed in one of the radial-directionwalls provided in the external wall.

The external air inlet hole may be located in a rear one of theradial-direction walls of the external wall with respect to therotational direction of the rotor.

The circumferential-direction wall may be inclined along thecircumferential direction in the narrow region or the wide region. Suchinclination may be linear or curved. The circumferential-direction wallis formed in a linear or curved shape.

A front portion of the radial-direction wall may be outer to a rearportion in the narrow region in a radial direction with respect to therotational direction of the rotor.

The external air inlet hole may be additionally formed in thecircumferential-direction wall in the narrow region. In other words, theexternal air inlet hole may be formed in at least predetermined area ofthe circumferential-direction wall.

The radial-direction wall may be bent perpendicular to the internal wallin the wide region.

The external wall of the external air supply channel may be continuouslyformed in a circumferential direction and the internal wall is bent inthe circumferential direction.

The internal wall may comprise a radial-direction wall facing theexternal wall in the narrow region; a radial-direction wall bent inwardin a radial direction to intersect the external wall in the wide region.

The external air inlet hole may be formed in one of the radial-directionwalls provided in the internal wall.

The external air inlet hole may be located in a rear one of theradial-direction walls of the internal wall with respect to therotational direction of the rotor.

The circumferential-direction wall may be inclined along thecircumferential direction in the narrow region or the wide region.

A front portion of the radial-direction wall may be outer to a rearportion in the narrow region in a radial direction with respect to therotational direction of the rotor. Such inclination may be formed linearor curved.

The external air inlet hole may be additionally formed in thecircumferential-direction wall in the narrow region.

The radial-direction wall may be bent perpendicular to the external wallin the wide region.

The internal wall and the external wall may be bent in thecircumferential direction.

The internal and external walls may comprise circumferential-directionwalls facing each other in the narrow region; and Radial-direction wallsbent in an opposite direction in the wide region.

The external air inlet hole may be formed in one of the radial-directionwalls in the wide region.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by illustration only, since various changes and modificationswithin the spirit and scope of the invention will become apparent tothose skilled in the art from this detailed description.

According to the embodiments of the present disclosure, the twin laundrymachine including a plurality of washing units configured to performwashing independently may be configured to set operations of motorsprovided in the washing units, respectively, not to be overlapped witheach other, when the washing units perform washing at the same time, anda control method of the same.

Furthermore, the laundry machine and the twin laundry machine arecapable of chilling a drive unit for driving a drum effectively and moreefficiently.

Still further, the laundry machine and the twin laundry machine iscapable of chilling a drive unit provided in a small-sized secondwashing unit thereof more effectively and efficiently.

Still further, the laundry machine and the twin laundry machine arecapable of chilling a drive-unit, especially, a stator of a motoreffectively.

Still further, the laundry machine and the twin laundry machine can berealized by changing a conventional structure of a rotor, even withoutinstalling or mounting an auxiliary component for chilling.

Still further, the drive unit has a structural stiffness and is capableof enhancing chilling efficiency by integral forming of an air inletstructure and an embossing structure as one structure, and each of thelaundry machine and the twin laundry machine including the drive unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given herein below and the accompanying drawings,which are given by illustration only, and thus are not limitative of thepresent invention, and wherein:

FIG. 1 is a schematic perspective diagram illustrating a rotor of amotor provided in a conventional laundry machine;

FIG. 2 is a perspective diagram of an air inlet part provided in therotor shown in FIG. 1 in a circumferential direction;

FIG. 3 is a perspective diagram illustrating a twin laundry machine inaccordance with one embodiment of the present disclosure;

FIG. 4 is a perspective diagram illustrating a twin laundry machine inaccordance with another embodiment of the present disclosure;

FIG. 5 is a block diagram illustrating a first washing unit and a secondwashing unit which are provided in the twin laundry machine inaccordance with the embodiment of FIG. 3;

FIG. 6 is a diagram illustrating the operations of motors provided infirst and second washing units of the twin laundry machine in accordancewith the embodiment of FIG. 3, respectively;

FIG. 7 is a diagram illustrating motions of the motors provided in thetwin laundry machine in accordance with the embodiment of FIG. 3;

FIG. 8 is a flow chart illustrating a control method of the first andsecond washing units provided in the twin laundry machine in accordancewith the embodiment of FIG. 3;

FIG. 9 is a flow chart illustrating the control method of the twinlaundry machine shown in FIG. 8;

FIG. 10 is a schematic sectional diagram partially illustrating a rotorin accordance with one embodiment of the present disclosure;

FIG. 11 is a schematic sectional diagram partially illustrating a rotorin accordance with another embodiment of the present disclosure;

FIG. 12 is a schematic sectional diagram partially illustrating a rotorin accordance with a further embodiment of the present disclosure;

FIG. 13 is a schematic sectional diagram partially illustrating a rotorin accordance with a still further embodiment of the present disclosure;and

FIG. 14 is a schematic sectional diagram partially illustrating a rotorin accordance with a still further embodiment of the present disclosure.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Preferred embodiments of the present invention will be described belowin more detail with reference to the accompanying drawings. Use of suchterminology for structures and control methods herein is merely intendedto facilitate description of the specification, and the terminologyitself is not intended to give any special meaning or function. In thepresent disclosure, that which is well-known to one of ordinary skill inthe relevant art has generally been omitted for the sake of brevity.

FIG. 3 is a perspective diagram illustrating a twin laundry machine asone embodiment of the present disclosure.

Referring to FIG. 3, the twin laundry machine 100 includes a firstwashing unit 140 and a second washing unit 150.

The first washing unit 140 and the second washing unit 150 are arrangedas top and bottom. The first washing unit 140 is arranged on the secondwashing unit 150 and the first and second washing units 140 and 150 areable to be connected with or disconnected from each other. In otherwords, the first and second washing units 140 and 150 have cabinets,respectively. The cabinets may be connectable and disconnected.Accordingly, it looks as if two washing units are provided in onecabinet.

As one alternative example, the first washing unit 140 and the secondwashing unit 150 may be provided in one cabinet. In this instance, thetwo washing units cannot be separated from each other.

The first washing unit 140 may be a front load twin laundry machine andthe second washing unit 150 is a top load twin laundry machine. At thistime, the first washing unit 140 may be a front load dryer or a frontload washer having a drying function and a washing function.

The front load twin laundry machine may mean a washing machine of whicha drum is rotary with respect to a substantially horizontal shaft,because it allows laundry to be loaded into the drum from a front sideto a rear side.

The top load twin laundry machine means a washing machine of which adrum for treating laundry is rotary with respect to a substantiallyvertical shaft, because it allows laundry to be loaded into the drumfrom a top side to a bottom.

The second washing unit 150 may be a drawer type structure which is ableto slide forward and backward so as to be open and closed. When thesecond washing unit 150 is pulled forward, a top end of the secondwashing unit 150 is shown. A second input unit 154, a second output unit152 and a second door 157 are arranged in the top end of the secondwashing unit 150.

The first washing unit 140 may include a first input unit 144, a firstoutput unit 142 and a first door 147. The second washing unit 150 mayinclude a second input unit 154, a second output unit 152 and a seconddoor 157.

Each of the first and second washing units 140 and 150 includes its owninput unit 154 or 156 and output unit 142 or 152, so that commands maybe input to the first and second washing units 140 and 150 independentlyand they can perform operations corresponding to the input commands,respectively.

Each of the first and second washing units 140 and 150 may include a tub148 and 158 for holding water; a drum 149 and 159 rotatably provided inthe tub; a motor rotating the drum; a water supply mechanism forsupplying water to the tub or the drum; and a drainage mechanism fordraining the water from the tub, so as to perform washing independently.

It is shown that the volume of the drum provided in the washing unit 140is larger than that of the drum provided in the second washing unit 150.Alternatively, it is possible that the volume of the drum mounted in thetub of the first washing unit 140 is smaller than that of the drumprovided in the second washing unit 150. In other words, it is preferredthat the volume of the drum provided in one of the washing units issmaller than that of the drum provided in the other one.

FIG. 3 shows that the second washing unit which is the top load typehaving the drum with the small volume is arranged under the firstwashing unit which is the front load type having the drum with the largevolume. Alternatively, the second washing unit is arranged on the firstwashing unit as the top. In the latter, it is not necessary that thesecond washing unit should be the drawer type. Different from theformer, the top where laundry is loaded is open. Accordingly, the secondwashing unit may be provided to prevent the drum from moving back andforth, like the conventional top load type. Even in this instance, thesecond door 157 may be provided.

The first washing unit 140 and the second washing unit 150 may be a twinlaundry machine having a washing function and a drying function.

FIG. 4 is a perspective diagram illustrating a twin laundry machine inaccordance with another embodiment of the present disclosure.

As shown in FIG. 2 (a), the twin laundry machine may be configured of afirst washing unit 140 a and a second washing unit 140 b which are allfront load type laundry machines.

The twin laundry machine has the second washing unit 150 b arranged onthe first washing unit 140 b. In other words, the second washing unithaving a drum with a small volume may be arranged on a top of the firstwashing unit having a drum with a large volume.

The twin laundry machine shown in FIG. 2 (b) may include a first washingunit 140 c and a second washing unit 150 c which are all of top loadlaundry machines.

The first washing unit 140 c and the second washing unit 150 c may bearranged side by side (or right and left), not as top and bottom.

Hereinafter, the illustrated embodiment shown in FIG. 3 provides thetwin laundry machine having the first washing unit 140 and the secondwashing unit 150 which are arranged as top and bottom. However, thearrangement and type of the first and second washing units is notlimited to what is shown and variable in diverse ways.

FIG. 5 is a block diagram illustrating the structure of the firstwashing unit and the structure of the second washing unit of the twinlaundry machine.

As shown in FIG. 5 (a), the first washing unit 140 includes a firstinput unit 144; a first output unit 142; a first tub 148; a first motor131; a first motor drive unit 130; a first sensor unit 160; a firstcommunication unit 180; a first data unit 120; and a first controller110 controlling an overall operation of the first washing unit 140.

As shown in FIG. 5 (b), the second washing unit 150 includes a secondinput unit 154; a second output unit 152; a second tub 158; a secondmotor 231; a second motor drive unit 230; a second sensor unit 260; asecond communication unit 280; a second data unit 220; and a secondcontroller 210 for controlling an overall operation of the secondwashing unit 150. In this instance, the structure of the second washingunit 150 is equal to that of the first washing unit 140 which will bedescribed hereinafter and detailed description about the structure ofthe second washing unit 150 is omitted.

The first input unit 144 includes input means such as one or morebuttons, a switch and a touchpad. A user inputs operational settingssuch as the power, washing courses, water levels and temperatures.

The first input unit 144 may include a simultaneous option key showingthat the first and second washing units 140 and 150 are operatedsimultaneously. Data about the simultaneous operation is input to thefirst controller 110, once the user manipulates the simultaneousoperation key. Unless such an auxiliary simultaneous operation key isprovided in the first input unit 144, the user may manipulate two of thebuttons simultaneously or at least two of the buttons in order to inputthe data about the simultaneous operation to the first controller 110.

The first output unit 142 displays information about the operationalsetting input to the first input unit 144. The first output unit 142includes a display for outputting an operational state of the twinlaundry machine and a speaker and a buzzer for outputting preset soundeffects or alarms.

In the first data unit 120 may be stored control data for controllingthe operation of the twin laundry machine, input operational settingdata, data about the washing courses, data for determining whether anerror occurs in the twin laundry machine. In addition, the data sensedor measured during the operation of the twin laundry machine and thedata transceived by the first communication unit 180 may be stored inthe first data unit 120.

The first communication unit 180 is connected to the second washing unit150 via wire or wirelessly and transceives data. In response to acontrol command of the first controller 110, the first communicationunit 180 transmits data about washing course setting or data accordingto the operation of the motor to the second communication unit andreceives data from the second communication unit.

The first sensor unit 160 includes a plurality of sensors and measuresvoltages or currents of the twin laundry machine and data about thetemperature, the water level and a state of the door to transmit themeasured data to the first controller 110.

For example, the first sensor unit 160 includes the sensors which areinstalled in different positions. The first sensor unit 160 senses awater level of wash water and transmits the sensed water level to thefirst controller 110. Also, it measures the temperature of wash water tosense the temperature inside a control circuit and the temperature ofthe heater in case a heater for heating or drying wash water isprovided.

The first motor drive unit 130 supplies the electric power so as torotatably drive the first motor 131 connected to the first tub accordingto the control command of the first controller 110. The first motordrive unit 130 controls a rotational direction, a rotational angle androtational velocity of the first motor 131 according to the presetsetting. Also, the first motor drive unit 130 controls the first motor131 to be driven differently according to the preset washing course, theongoing washing, rinsing and spinning.

In this instance, the first motor drive unit 130 controls the rotationaldirection, rotational angle and rotational velocity of the first motorto be differentiated so as to form specific water currents in the firsttub 148.

The first motor drive unit 130 controls the first motor 131 to formspecific water currents by combining one or more operations of the firstmotor 131, for example, clockwise rotation, pausing, counter-clockwiserotating, rotating at a high or low velocity for a preset time period.Accordingly, the motions of the first motor give specific washingeffects to the laundry loaded in the first tub 148.

The operations for forming specific water currents by combining themotor operations to give one of washing effects including entangling,soaking, detergent dissolving and laundry rubbing may be set as onemotion. The first motor drive unit 130 classifies the operations forwashing, rinsing and spinning by motion unit so as to control the motor131.

In this instance, the first motor drive unit 130 controls one motion tobe performed for a preset operation period. Also, it controls theoperations of the motor which consists of one motion to be setdifferently for each motion. The operation period as the time periodtaken to perform one motion one time is set differently for each motion.

The first controller 110 applies a control command to a first valvecontroller 170 and the first motor drive unit 130 according to theoperation setting transmitted from the first input unit 144 so as toperform water supply or drainage of the first tub 148. Then, the firsttub 148 is rotated according to the operation of the first motor 131 andwashing is performed. The first controller 110 controls a series ofwashing processes such as washing, rinsing and spinning. That is, thefirst controller 110 stores the input operational setting in the firstdata unit 120 and outputs the operational setting or operational stateon the first output unit 142. Also, the first controller 110 controlsthe first communication unit 180 to transmit the operational data to thesecond washing unit 150.

The first controller 110 applies a control command to the first motordrive unit 130 by classifying the operations of the first motor forperforming washing, rinsing and spinning cycles according to the washsetting by motion unit and a control command and applies a controlcommand to the first motor drive unit 130 on a basis of the operationperiod which is the time period taken for the first motor to perform onemotion one time.

At this time, the first controller 110 controls the operation period ofthe second motor 231 provided in the second washing unit not to beoverlapped with the operation period of the first motor by transceivingdata with the second washing unit via the first communication unit 180.

When driving or pausing the motor even in case the first and secondwashing units perform washing simultaneously, the first controller 110and the second controller 210 controls the operational periods not to beoverlapped with each other by checking an operation-on period and anoperation-off period of the motors based on the data transceived witheach other and alternatively operating the first and second motors, notoperating the motors simultaneously.

In other words, the first controller 110 and the second controller 210transceives data with each other via the communication unit consistentlyand controls the second motor 231 to pause the operation and standby,when the first motor 131 performs one motion, and controls the firstmotor to standby and the second motor 231 to perform a preset motion,once the motion of the first motor is complete.

In this instance, the first controller 110 and the second controller 210sets an operation-off period of one motor in response to the size of theoperation-on period of the other motor, so as to control an operation-onperiod and an operation-off period for each motion of the first andsecond motors 131 and 231.

For example, when the first motor is operated alone, the first motorperforms a first motion for a first operation-on period and thenstandbys for a second operation-off period and then performs a secondmotion for a third operation period. When the first and second motorsare operated simultaneously, the first motor performs the first motionfor the first operation-on period and standbys for the secondoperation-off period. At this time, the first motor starts to performthe second motion once the second operation-on period of the secondmotor finishes, not starting to perform it right away.

Accordingly, the overall washing time is increased as much as the sizeof the operation-off period increases. The first controller 110 and thesecond controller 210 reflects the increased washing time enabled bycontrolling the motor according to the transceived washing setting inthe initial stage and then calculates the washing time. The first andsecond controller 110 and 210 may change the washing time during thewashing process and display the changed washing time.

FIG. 6 is a diagram illustrating the operations of the motors providedin the first and second washing units of the twin laundry machine inaccordance with the illustrated embodiment. FIG. 6 (a) is a diagramillustrating the operation of the first motor 131 and FIG. 6 (b) is adiagram illustrating the operation of the second motor 231.

As shown in FIGS. 6 (a) and (b), the first motor drive unit 130 controlsthe first motor 131 according to the control command of the firstcontroller 110. The second motor drive unit 230 controls the secondmotor 131 according to the control command of the second controller 210,so that such the operations of the first and second tubs 148 and 158 maygive the laundry loaded therein preset washing effects.

The first communication unit 180 and the second communication unit 280transceives data with each other according to the control commands ofthe first controller 110 and the second controller 210, respectively.

The first motor drive unit 130 controls the first motor 131 according tothe control command of the first controller 110. Accordingly, the firstmotor 131 performs the first motion for the first operation-on periodfrom the zero time (T0) to a first time (T1) and standbys (or pauses orbecomes off) from the first time (T1).

Meanwhile, the second motor drive unit 230 controls the second motor 231according to the control command of the second controller 210. At thistime, the second controller 210 determines whether the first motor 131starts to operate at the zero time (T0) based on the data transmittedfrom the first washing unit and sets an operation-off period in whichthe second motor standbys. The second motor drive unit 230 controls thesecond motor 231 to pause and standby from the zero time (T0) to thefirst time (T1).

As the operation-on period of the first motor 131 finishes at the firsttime (T1), the second motor drive unit 230 controls the second motor 231to be operated for the second operation-on period from the first time(T1) to a second time (T2) according to the control command of thesecond controller 210.

In case the first motor 131 is operated alone, the operation-off periodof the first motion performed for the first operation-on period is fromthe first time (T1) to a first 1-1 time (T1-1) and then the first motor131 starts to operate the next motion. At this time, the 1-1 time (T1-1)is the operation-on period of the second motor 231 and the controller110 sets the operation-off period of the first motor 131 is set to bechanged from the period from the first time (T1) to the 1-1 time (T1-1)into the period from the first time (T1) to the second time (T2).

Accordingly, the first motor drive unit 130 controls the first motor 131to standby in a state of pausing or operation-off from the first time(T1) to the second time (T2) and to starts to operate at the second time(T2).

The first controller 110 increases the operation-off period of the firstmotor as long as from the 1-1 time (T1-1) to the second time (T2) andalso increases the washing time as much as the operation-on period ofthe first motor is delayed.

The operation-on period of the first motor 131 is set from the secondtime (T2) to a third time (T3) and the first motor 131 performs a presetmotion according to the control of the first motor drive unit 130.

At this time, the second controller 210 sets the operation-off time ofthe second motor 231 from the second time (T2) to the third time (T3)and the second motor drive unit 230 pauses and standbys the second motor231 according to the setting.

Accordingly, the second motor 231 standbys until the third time (T3) andstarts the operation from the third time (T3) to a fourth time (T4). Atthis time, the first motor 131 standbys and starts the operation fromthe fourth time (T4) to a fifth time (T5) while the second motor 231standbys.

The first controller 110 and the second controller 210 sets theoperation-on period and the operation-off period to operate the firstmotor and the second motor reversely and not to overlap the operationswith each other. when the first controller 110 and the second controller210 transceives data with each other via the communication unit, whenone operation-on period starts and finishes, only to repeat theoperation-on period and the operation-off period.

In this instance, for the operation-on periods of the first and secondmotors, the same motion may be continuously performed or differentmotions may be performed. When different motions are performed, the sizeof the periods may be set different.

FIG. 7 is a diagram illustrating the motions of the motors provided inthe twin laundry machine.

For the operation-on periods described with reference to FIG. 6, thefirst motor 131 and the second motor 231 perform one or more presetmotions. One motion is configured of several operations combined withone or more of clockwise rotation, pausing, counter-clockwise rotation,high-velocity rotation and low-velocity rotation so as to form specificwater currents or give laundry washing effects.

For example, one motion gives laundry one of the entangling, soaking,detergent dissolving and rubbing washing effects.

As shown in FIG. 7, the first motor 131 performs the motion configuredof several operations from the second time (T2) to the third time (T3).

For example, the first motor 131 repeats the operation three times inwhich it rotates and pauses at a first rotation number for a first timeperiod controlled by the first motor drive unit 130, another operationin which it rotates at a second rotation number lower than the firstrotation number for a second time period and the pauses and the otheroperation in which it rotates at the first rotation number for a thirdtime period.

During the one operation-on period, the motor may perform severaloperations or one operation continuously.

The operations mentioned above are examples of the operations accordingto the illustrated embodiment and not limited to what is shown in thedrawings. Each of the motions may include several different operations.

FIG. 8 is a flow chart illustrating a control method of the first andsecond washing units provided in the twin laundry machine in accordancewith the embodiment of FIG. 3.

As shown in FIG. 8, when the first washing unit 140 and the secondwashing unit 150 are operated simultaneously, the first controller 110applies a control command for motor driving to the first motor driveunit 130 along the washing process of the first washing unit 140configured of washing, rinsing and spinning cycles. At this time, thefirst controller 110 transceives data about mutual motor driving withthe second controller 210 of the second washing unit 150 via the firstand second communication units 180 and 280, to set the operation-onperiods of the motors not to be reversed, not overlapped with eachother. The first controller 110 and the second controller 210 may setthe operation-off period for each of the first and second motors,respectively, corresponding to the operation-on periods of the othermotor.

The first controller 110 receives an operation command of the firstwashing unit according to washing settings and controls the firstwashing unit based on the operation command (S310).

The first controller 110 determines whether the second motor is beingoperated before driving the first motor 131 (S320).

The first controller 110 controls the first motor 131 to standby inresponse to data about the operation of the second motor transmitted viathe first communication unit 180, in case the second motor performs theoperation for a preset operation-on period (S330).

Meanwhile, the first controller applies a control command to the firstmotor drive unit 130 for the first motor 131 to perform operationsaccording to a preset motion and transmits data about the operation-onperiod and operational state of the first motor 131 to the secondwashing unit, when the second motor 231 pauses the operation in itsoperation-off period (S340).

The first motor drive unit 130 applies an operation power to the firstmotor 131 according to the control command and drives the first motor toperform the motion combined with one or more of the clockwise rotation,pausing, counter-clockwise rotation, high-velocity rotation andlow-velocity rotation for the first operation-on period.

At this time, the second controller 210 receives the data about theoperation-on period of the first motor via the second communication unit280 and sets the operation-off period of the second motor to standby thesecond motor in the state of pausing. The operation-off period of thesecond motor is corresponding to the operation-on period of the firstmotor.

After the first motor 131 completes all of the operations configured aspreset one motion for the first operation-on period, the firstcontroller 110 transmits data about the operation pause state and theoperation-off period of the first motor 131 to the second washing unitvia the first communication unit 180 (S350).

The first controller 110 controls the first motor drive unit 130 topause the first motor for the second operation-off period setcorresponding to the operation-on period of the second motor.

Once the second operation-off period ends, the first controller 110transmits data to the second washing unit 150 and determines whether thesecond motor is operated based on the response of the data transmission(S360). The first controller 110 controls the first motor to standbyunless the operation-on period of the second motor 231 finishes (S370).

Unless the second motor 231 is operated, in other words, when theoperation-on period of the second motor 231 ends or the second motor 231is in the operation-off period, the first controller 110 applies acontrol command to the first motor drive unit 130 and transmits dataabout the operation-on period of the first motor to the second washingunit.

The first motor drive unit 130 controls the first motor to performoperations of a preset motion for the third operation-on period (S380).

Those processes are repeatedly performed until the preset washingsetting is complete (S390).

FIG. 9 is a flow chart illustrating the control method of the twinlaundry machine shown in FIG. 8.

As shown in FIG. 9, the first washing unit 140 and the second washingunit 150 transceive data with each other via the first and secondcommunication units 180 and 280 and determine the operational states ofthe motors.

When the first motor 131 performs the operations configured as onemotion for the first operation-on period (S410), the first controller110 transmits an operation alarm according to the operation-on period ofthe first motor to the second washing unit 150 (S420) and the secondwashing unit 150 transmits a response signal for identifying the alarmreceiving.

The second washing unit 150 determines the first operation-on period ofthe first motor based on the operation alarm and sets the firstoperation-off period of the second motor in response to the firstoperation-on period of the first motor to standby the first second motor(S430).

Once the first motor 131 completes the operations of the motion, thefirst motor drive unit 130 pauses the first motor. At this time, thefirst controller 110 transmits a pausing alarm in response to theoperation-on period finishing of the first motor to the second washingunit (s450). The second washing unit 150 transmits a response signal foridentifying the alarm receiving.

The second washing unit 150 sets the second operation-on period of thesecond motor 231 as the first operation-on period of the first motor 131ends and the second motor performs the operations of the preset motionfor the second operation-on period (S460).

At this time, the second controller 210 of the second washing unit 150transmits an operation alarm for the second operation-on period of thesecond motor to the first washing unit 140 (S470). The first washingunit 140 transmits a response signal for identifying the alarmreceiving.

The first controller 110 sets the second operation-off period of thefirst motor, corresponding to the second operation-on of the secondmotor 231 and controls the first motor to standby (S480).

Once the second motor pauses after completing the operations (S490), thesecond controller 210 transmits a pausing alarm of the second motor tothe first washing unit 140 (S500). The first washing machine transmits aresponse signal for identifying the alarm receiving.

The first controller 110 sets the third operation-on period of the firstmotor and operates the first motor for the third operation-on period.

The first and second washing units 140 and 150 categorize all of theoperations including washing, rinsing and spinning cycles performed bythe motor by motion unit and set the operation-on periods and theoperation-off periods of the first and second motors via mutualcommunication, so that they may control the first and second motors notto be operated simultaneously.

Even if the washing units are operated simultaneously, the operations ofthe first motor and the operations of the second motor are set inreverse and the operation-on periods of the first motor are notoverlapped with the operation-on periods of the second motor.Accordingly, the increase of vibration and drastically high powerconsumption may be prevented and energy use efficiency may be improved.

The embodiments of the twin laundry machine including the first andsecond washing units and the control method of the same are describedwhich provides more confidence in the product's reliability when thefirst and second washing units are operated simultaneously.

As mentioned above, the twin laundry machine seems to mean one laundrymachine and one laundry machine including two sub-washing machines.Accordingly, the user is able to use each of the sub-washing machines ofthe twin laundry machine independently and feels like using one machine.

Therefore, the user can think that the product has some problems notproblems of components, if one of the tub-washing machines fails to beoperated smoothly and normally. For example, if an error occurs in thesecond washing unit, the user thinks that there is an overall problemwith the twin laundry machine. Such the twin laundry machine is notprovided with the first and second washing units separately but providedby one supplier, so that it may be quite important to provide the userwith the confidence in the product's reliability.

If they are separated independently, the first washing unit and thesecond washing unit are not high-value products. However, if they areprovided as one twin laundry machine, the twin laundry machine may beone of the high-value premium products.

The embodiments described above may be to drive the overall twin laundrymachine smoothly and efficiently and embodiments which will be describedlater are to drive the second washing unit having a small drum volumesmoothly and efficiently. In other words, according to the embodimentswhich will be described later, the second washing unit may be drivensmoothly and the twin laundry machine's reliability and durability maybe enhanced.

As mentioned above, the drum 159 of the second washing unit is orientedto rotate with respect to the vertical shaft and laundry may be loadedinto the drum from the top to the bottom. Compared with the size of thefirst washing unit, the second washing unit has the small size and it ispreferred that the second washing unit is higher than the first washingmachine. In case it is an independent and separate washing machine, thesecond washing unit has the improved reliability and durability as itis.

The small size of the washing unit results in the small volume of thedrum 159. To prevent the volume of the drum from becoming too small, itis preferred that a diameter of the drum 159 is larger than the height.Corresponding to the shape and the size of the drum, the shape and sizeof the tub may be determined.

The limited height of the second washing unit causes the limited heightof the drive unit for driving the drum, especially, the motor. That isbecause the height of the second washing unit is increased if the heightof the motor is increased.

As mentioned above, the second washing unit is mainly used in washing asmall amount of laundry or washing laundry in boiling water.

Considering the characteristics of the top load twin laundry machine andthe height of the second washing unit, it is obvious that a very narrowspace is formed between the lowermost surface of the tub and thelowermost surface of the second washing unit.

Wash water is heated by a tub heater provided in the tub in asterilize-washing course and the heat generated while wash water isheated has to be radiated. However, the space is too small to radiatethe heat naturally.

A stator is coupled to an outer side surface of the tub, especially, alower outer surface and it is known that there is much room fortransferring heat inside the tub to the stator. In this instance, theheat generated in the stator and the heat transferred to the stator fromthe tub has to be radiated effectively. In other words, the stator hasto be chilled effectively. Otherwise, the motor might be damaged or itcould be difficult to drive the motor efficiently.

As mentioned above, the unsmooth driving of the second washing unit is amatter of the twin laundry machine, not the matter of the second washingunit. The user purchases and uses the entire twin laundry machine fromone manufacturer or one seller of the product. The user recognizes thetwin laundry machine as one high-value premium product.

Referring to FIGS. 10 through 14, embodiments for chilling the motor fordriving the drum in the twin laundry machine effectively will bedescribed in detail. Especially, the motor or a rotor of the motoraccording to one embodiment is applied to the second washing unit of thetwin laundry machine.

The same or similar characteristics of the conventional rotor described,referring to FIGS. 1 and 2, are omitted. The drive unit for driving thedrum which includes the motor is well known in the art to which thepresent disclosure pertains and detailed description of the drive unitis also omitted. Specifically, the drive unit for driving an outer typemotor (a motor having a stator and a rotor rotary along an outer radialdirection with respect to the stator) includes a stator; a drum shaft, aconnector for connecting the rotor and the drum shaft with each other; astructure for coupling the stator to the tub; a spider for coupling thedrum shaft to the drum. Such the drive unit may not belong to thetechnical features of the present disclosure. Accordingly, the detaileddescription of such the drive unit is omitted. Embodiments of the rotorwhich will be described herewith may be applicable to the conventionaldrive unit.

First of all, one embodiment of the present disclosure will be describedreferring to FIG. 10.

In the illustrated embodiment, a rotor frame 320 of a rotor 300 includesa side wall 330; a bottom wall 340; and an air inlet part 341. One ormore magnets 360 may be provided in the side wall 330.

The air inlet part 341 may be extended in a radial direction and aplurality of air inlet parts 341 may be provided. The plurality of theair inlet parts 341 may be arranged along a circumferential directionand they may be spaced apart a preset uniform distance from each otherin the circumferential direction.

The air inlet part 341 may include an opening 343 and the opening may beprovided in the rotor frame 320. The opening 343 may be verticallyformed in the bottom wall 340. Accordingly, external air is not suckedtoward the stator from the outside of the rotor (a vertical upwarddirection in FIG. 10) but sucked from the outside of the rotor in acircumferential direction. In other words, external air is sucked intothe rotor in a direction which is parallel with a direction along therotation axis of the rotor or a rotational direction of the rotor, not avertical direction with respect to the rotation axis of the rotor.Accordingly, the suction direction of external air is not distorted orcurved so that external air can be sucked into the rotor more smoothly.

To form such the opening 343, the air inlet part 341 includes aplurality of side walls. Such side walls may be integrally formed withthe bottom wall 340 of the rotor frame 320.

Specifically, a cut-way portion 349 extended in a radial direction maybe formed in the bottom wall 340. The side wall 330, the bottom wall 340and the hub 350 of the rotor frame 320 is integrally formed with eachother and made of a steel material by pressing.

In the pressing, a projected portion 342 may be formed while the bottomwall 340 near the cut-away portion 349 is pushed upward. At this time,the opening 343 may be formed and the area of the opening 343 equals toa value gained by multiplying the length of the cut-away portion 349 bythe height of the projected portion.

The projected portion 342 may be projected to a preset height toward thestator from the bottom wall 340. In a view of the reversed rotor frame320, the projected portion 342 may be a recessed portion.

The projected or recessed portion may be formed by the plurality of theside walls only to form a preset space. External air is drawn into suchthe projected portion consistently so that it may be a channel forguiding air flow into the rotor frame via the opening 343. External airis sucked into the rotor along the channel and the channel may bereferred to as the external air inlet channel 342 to be distinguishedfrom a channel which will be described later.

Specifically, an inner wall 346 formed in an inner radial portion and anouter wall 345 formed in an outer radial portion may be furtherprovided. The inner wall 346 and the outer wall 345 may be extendedalong a circumferential direction, so that they may be formed in alinear or curved shape.

A top of the inner wall 346 and a top of the outer wall 345 areconnected with each other via an upper wall 348. The upper wall isprojected upward, compared with the bottom wall 340 of the rotor frame.The bottom wall and the upper wall may be substantially perpendicular toeach other. Accordingly, the upper wall is extended from a top of theinner wall toward the outer wall in an outer radial direction, to beconnected to a top of the outer wall.

A front wall 347 may be formed in opposite to the opening 343 in thecircumferential direction. The front wall may be extended from thebottom wall 340 in a substantially perpendicular direction with respectto the stator, like the inner wall and the outer wall. The front wallmay connect the inner wall and the outer wall with each other.

In this instance, the front wall is named after the rotational directionof the rotor. A rear wall opposite to the front wall may be formed andit can be said that the opening 343 is formed in the rear wall.

Accordingly, the projected or recessed portion is formed like some spacewith the blocked top, right and left sides and front. The opening isformed in a rear portion of the projected or recessed portion. A bottomof the projected or recessed portion is open and a bottom of theexternal air inlet channel is open.

The volume of the external air inlet channel may be schematically set asfollows. On explanation convenience sake, assume that the inner wall andthe outer wall are the same lines with the same length. In thisinstance, the volume equals to a value gained by multiplying the lengthof the inner wall (or the outer wall), the length of the cut-awayportion (or the front wall) by the projected height of the projectedportion.

In other words, a certain space corresponding to the volume of theprojected portion is formed in an outer portion of the rotor frame 320,specifically, the bottom wall 340 of the rotor frame. Such a space maybe in direct communication with the opening 343.

When the rotor 300 is rotated in a clockwise direction, air may besucked into the rotor frame 320 from the projected portion via theopening. Of course, new external air is filled in the external air inletchannel 342 and sucked into the rotor frame again. Cold air is notsucked into the rotor frame manually as hot air inside the rotor frameis exhausted from the rotor frame. Hot air is exhausted from the rotorframe as hold air is sucked into the rotor frame positively.Accordingly, the amount of air flow increases and the suction of coldair into the stator is facilitated enough to chill the stator.

Meanwhile, the opening 343 may be configured to exhaust air from oneexternal air inlet channel 342. In other words, the opening 343 isdefined by the bottom wall 340, the outer wall 345, the inner wall 346and the upper wall 348 and the air guided by the walls can be suckedinto the rotor frame 320 via the opening 343.

If assuming that the external air inlet channel is extended in thecircumferential direction, the air guided by the bottom wall 340, theouter wall 345 and the inner wall 346 of the rotor frame is sucked intothe rotor frame 320.

Accordingly, the vertex generated by the drastic change of the air flowdirection near the opening 343 and vertex may be noticeably reduced andthe flow velocity and flow amount of the air sucked via the opening 343may be noticeably increased. The increase of the air flow velocity andair flow amount mean the increase of the chilling efficiency of thestator.

The external air inlet channel 342 is projected or recessed from thebottom wall and extended in the circumferential direction, with at leastthree surfaces, to be connected with the opening 343. The channel is thespace in which external air is collected and is a guide space guidingexternal air to the opening 343.

The connector is coupled to the hub 350 formed in the center of thebottom wall 340 of the rotor frame 320. To couple the connector to thehub stably, a level surface 351 projected from the bottom wall 340 isprovided. An outer surface 353 and an inner surface 352 may be formed inan outer portion and an inner portion with respect to the radialdirection, respectively.

It is preferred that an inner surface of the hub is formed as asubstantially vertical surface and that the inner surface has apredetermined radius. That is because the drum shaft is inserted throughthe inner surface.

The outer surface of the hub may have an inclined surface and theinclined surface may be inclined upward to the center.

The level surface, the inner surface and the outer surface of the hubare formed to be fitted to the connector. The connector formed to befitted to the surfaces is coupled to the rotor frame 320 toward the topof the rotor frame so that the connector can be securely fitted to thehub in the radial direction. The axial and circumferential directioncoupling force between the connector and the hub may be secured byauxiliary coupling means such as a bolt.

Different from what is described above, the level surface of the hub maybe a predetermined portion of the bottom wall of the rotor frame. Inother words, the level surface has the same plane as the bottom wall.

Comparing FIG. 1 with FIG. 10, no embossing portion 44 is shown in FIG.10. Specifically, the external air inlet channel forming the air inletpart 341 is capable of reinforcing the stiffness of the bottom wall 340.If assuming that the rotor shown in FIG. 1 is equal to the rotor shownin FIG. 10 in size, twice as many as the air inlet parts may be formedaccording to the illustrated embodiment. In other words, the number ofthe air inlet parts may be increased even with the same radial length ofthe opening 343 for sucking air into the rotor.

However, it is limited to increase the height of the opening 343 asmentioned above and it is also limited to increase the overall area ofthe opening by increasing the height of the opening 343. As the opening343 is formed in the bottom wall 340, it is also limited to increase theradial length of the opening. Especially, it is preferred that theopening is formed between the side wall 330 and the hub 350 and it islimited to increase the radial length of the opening.

The opening 343 may contact with the side wall 330. In this instance,there may be no space where the side wall is able to bend and where theouter wall 345 is able to bend or there may be a narrow space. It ispreferred that a predetermined radial space length is formed between theside wall 330 and the outer wall 345.

The opening 343 may contact with the hub 350. In this instance, theremay be no space where the inner wall 346 is able to bend and where thehub 350 is able to bend or there may be a narrow space. It is preferredthat a predetermined radial space length is formed between the hub 350and the inner wall 346.

Meanwhile, the relation between the area of the opening and the flowamount and velocity of air will be described. The area of the opening isincreasing as the radial length of the opening is increased.

If the same flow amount of air is sucked via the opening, regardless ofthe area of the opening, the area of the opening is small and the airflow velocity is increased more. The location of the opening isapproximately corresponding to the location of the coil provided in thestator. When the length of the opening is increased, the area of theopening is increased and the air flow velocity is lowered, and air mayflow in a direction which is irrelevant to the stator coil. When thelocation of the opening is corresponding to the location of the statorcoil even with the reduced area of the opening, air may intensively flowto the stator at the increased flow velocity. In this instance, it ispreferred that consecutive bottom walls 340 are provided in a radialouter portion and a radial inner portion with respect to the opening343. In other words, it is not preferred that the opening is extendedeven to the radial outer portion or to the radial inner portion from aradial direction of the stator coil.

When the volume of the external air inlet channel near the opening 343is increased, not the number of the openings 343 is increased, thechilling efficiency may be enhanced more effectively. As the openingsfor sucking air along the circumferential direction are formed more andmore densely, the overall radial consecutive air flow is interfered moreand more.

Not the number of the openings 343 but the volume of the external airinlet channel is increased to allow more external air to be sucked intothe rotor frame 320 via the opening 343 effectively. In the embodimentshown in FIG. 10, a circumferential-direction gap between the air inletpart 342 becomes larger than the circumferential-direction length of theair inlet part 341.

Specifically, the air inlet part 341 includes the inner wall 346 and theouter wall 345. It is preferred that the circumferential-directionlength of the inner wall 346 is different from that of the inner wall346. In other words, the inner wall 346 may be longer than the outerwall so that the air inlet part 341 may be formed in a fan shape.

The circumferential-direction gap between the air inlet parts 341 may belarger than the circumferential-direction length of the air inlet part341. As the circumferential-direction length of the channel 342 isincreased, the sizes become different from each other. In other words,as the circumferential-direction length of the channel 342 is increased,the circumferential-direction gap between the air inlet parts 341becomes smaller than that of the air inlet part 341.

At this time, the air sucked via one of the air inlet parts 341 may runagainst the front wall 347 of the air inlet part 341 nearby only tointerfere with smooth air flow. To solve that, the front wall 347 andthe upper wall 348 may form an acute angle, not the right angle.Alternatively, the front wall 347 and the upper wall 348 may beconnected with each other by a curved line and both of the walls formone curved wall. In this instance, the angle or shape formed by the rearwall and the upper wall becomes different, the shape of the outer wall345 and the inner wall 346 may become different.

To achieve the object that the volume of the projected portion 342 inwhich external air is stored has to be increased and that one air inletpart has not to interfere with the flow of the air sucked via theneighboring air inlet part, the embodiment shown in FIG. 12 may beproposed.

As shown in the drawing, the plurality of the air inlet parts may beformed along a radial direction consecutively. At this time, the rearwall and the upper wall 348 of the air inlet part 341 may be formed asone inclined wall or curved wall. The air sucked via one air inlet part341 rises and flows along the inclined or curved wall of one neighboringair inlet part in the circumferential direction. The smooth air flow andair rise may be performed by structural characteristics of the projectedportion 342.

In the illustrated embodiment, the plurality of the air inlet parts 341may be consecutively arranged along the circumferential direction. Thecircumferential-direction length of the outer wall 346 has to be longerthan the circumferential-direction length of the inner wall 346.

Hereinafter, another embodiment of the present disclosure will bedescribed referring to FIG. 13. The embodiment shown in FIG. 13 may becombinedly applied to the embodiment described referring to FIGS. 10through 12.

According to the illustrated embodiment similar to the embodimentsmentioned above, the external air inlet channel 342 is provided and anexternal air supply channel 365 in communication with the external airinlet channel 342 may be provided.

As mentioned above, external air is collected via the external air inletchannel 341 and the collected air may be guided into the rotor frame320. It is preferred in the illustrated embodiment that the external airsupply channel 365 is formed to suck a large amount of external air intothe external air inlet channel 341, eventually, the rotor frame 320.

The external air supply channel 365 is the channel formed in thecircumferential direction and recessed or projected from the bottom wall340. The bottom wall 340 is partially projected toward the stator toform the external air supply channel 365.

The externa air supply channel 365 may be formed in a ring shape and inan inner portion with respect to the radial direction of the externalair inlet channel 342. Specifically, the external air supply channel 365may be formed between the external air inlet channel 342 and the hub350.

The projected height of the external air supply channel 365 may be equalto that of the external air inlet channel 342. Accordingly, the upperwalls of the both channels may be consecutive at the same height.

In this instance, the external air supply channel 365 may be incommunication with the external air inlet channel 342.

The external air supply channel 365 includes an inner wall 363 and anouter wall 361. The inner wall may be formed consecutively along thecircumferential direction. In other words, the inner wall is completelyblocked along the circumferential direction. The outer wall 361 and theinner wall 363 may be connected with each other by the upper wall 362.The upper wall 362 may be the level wall projected upward from thebottom wall 340.

The outer wall 361 may be formed along the circumferential direction notconsecutively but intermittently. Specifically, the external air inletchannel 342 communicates with the external air supply channel 365through the area in which the outer wall 361 is not formed.

The outer wall 361 may be may be extended from the opening of one airinlet part 341 to the front wall 347 of the neighboring air inlet part341.

Such the external air supply channel 365 may provide following effects.

The external air supply channel 365 is configured to collect the airflow along the circumferential direction from an outer bottom surface ofthe rotor frame 320. As the rotor frame 320 is rotated, air near theexternal bottom surface of the rotor frame is collected in the externaair supply channel 365. Especially, ambient air in the center of therotor frame flows in an outer radial direction and be collected in theexternal air supply channel 365.

The air flowing along the external air supply channel 365 is guided tothe external air inlet channel 342 to be sucked into the rotor.

To suck air via one opening 343, air has to be sucked in an innerradial-direction portion and an outer radial-direction portion of theopening smoothly. Accordingly, the air flow is collected in the innerradial-direction portion through the external air supply channel 365 andsupplied to the external air inlet channel 342.

The air may be sucked into the rotor more smoothly and effectively thana large amount of external air.

Meanwhile, the external air supply channel 365 and the external airinlet channel 342 may be provided as one channel. At this time, an outerwall of the external air inlet channel may be a first wall and an outerwall of the external air supply channel may be a second wall. An innerwall of the external air supply channel may be a third wall. Those wallsmay be spaced a preset distance apart from each other in the radialdirection.

When the external air supply channel and the external air inlet channelare provided as one channel, a side wall having an opening may be afirst side wall and a front wall of the external air inlet channel maybe a second side wall. Upper walls of the external air inlet channel andthe external air supply channel may be third side walls.

Accordingly, the uni-channel may be formed by the first wall, the secondwall, the third wall, the first side wall and the third side walls. Asmentioned above, the second side wall and the third side wall may form auni-side wall by using one inclined or curved surface.

The external air supply channel 365 will be described in detail. Whilethey are described as independent components in the embodiment describedabove, the external air supply channel 365 and the external air inletchannel 342 are united as one channel.

In the illustrated embodiment, the external air supply channel 365 isformed in the rotor frame 320 to suck a much amount of external air intothe rotor frame 320.

The external air supply channel 365 is formed along a circumferentialdirection and recessed or projected from the bottom wall 340 of therotor frame 320 so that external air outside the rotor frame 320 can becollected and flow. In other words, a predetermined region of the bottomwall 340 is projected toward the stator and an outer region of thebottom wall is recessed in a circular shape. Specifically, seen from theinside of the rotor frame 320, the external air supply channel 365 isprojected in a circular shape. Seen from the outside of the rotor frame320, the external air supply channel 365 is recessed in a circularshape.

The external air supply channel 365 may include an external wall 363 andan external wall 361. The external wall 363 is completely embedded alonga circumferential direction. The external wall 361 may be formed tocommunicate with an internal space of the external air supply channel365 along the circumferential direction. One or more certain sections ofthe outer wall 361 are blocked and another one or more certain sectionsare open, so that internal air of the external air supply channel 365may flow outside through the open sections of the external wall 361.

The blocked sections and the open sections may be alternatively formedin the external wall 361 along the circumferential direction.

It is preferred that the outer wall 361 is connected with the internalwall 363 via the upper wall 362. It can be said that the upper wall 362is a horizontal wall projected from the bottom wall 340.

When the upper wall 362 is formed by pressing, the upper tall 362 may bepartially projected to the outside of the frame (in the reversedirection of the stator). In other words, a predetermined portion of thehorizontal upper wall 362 is projected downward to serve as a blade 362a for facilitating flow of external air in the external air supplychannel 365.

As one alternative embodiment, the external wall 361 may be bendingalong the circumferential direction. The external air supply channel 365may include a narrow region 381 having a narrow width (h) and a wideregion 382 having a relatively wide width (H) between the internal wall363 and the external wall 361. In this instance, the width (H) is largerthan the width (h). Specifically, the external wall 361 is extendedalong the circumferential direction in the narrow region 381 and thewide region 382 and along a radial direction in a region in which thenarrow region meets the wide region. Accordingly, the internal wall ofthe external air supply channel 365 is a continuous wall with the sameradius and the external wall is a wall formed by alternative connectingof a wall with a small radius and a wall with a large radius. To put itplainly, it can be said that the external wall of the external airsupply channel 365 is formed in a serration (or a saw-tooth) shape.

More specifically, the external wall 361 may include a wall in acircumferential direction (hereinafter, “a circumferential-directionwall) 361 a facing the internal wall 363 in the narrow region 381; and awall in a circumferential wall (hereinafter, a circumferential-directionwall) 361 b facing the internal wall 363 in the wide region. Theexternal wall 361 may include a wall in a radial direction (hereinafter,a radial-direction wall) 361 c bending in a radial direction tointersect the internal wall 363. The radius of thecircumferential-direction wall 361 a is smaller than that of the othercircumferential-direction wall 361 b.

An external air inlet part 373 may be formed in the radial-directionwall 361 c of the external wall in opposite to one end of the narrowregion 381. The external air inlet part 373 may be the sameconfiguration as the opening 343 in an aspect of the external air inletchannel 342. In this instance, the radial-direction wall 361 c may beconfigured of a front wall portion and a rear wall portion with respectto the rotational direction of the rotor frame 320. It is preferred thatthe external air inlet part 373 is formed in the rear wall portion.

While spread in the wide region 382, the external air penetrating thenarrow region 381 via the external air inlet hole 373 can be sucked intothe external air inlet hole 373. The radial-direction wall in oppositeto the external air inlet hole 373, in other words, the front wallportion may be configured to cause flow of external air in the externalair supply channel 365, in other words, function as blade.

The external wall 361 a of the narrow region 381 may be inclined. Inother words, the one end of the circumferential-direction wall of thenarrow region 381 is formed outer or inner to the other end in a radialdirection. It is preferred that a front portion is outer to a rearportion in a radial direction with respect to the rotational directionof the rotor. In this instance, the radial-direction length of the frontwall portion is larger than that of the rear wall portion in theradial-direction wall 361 c. Accordingly, the external air supplychannel 365 may be formed in pin wheel shape.

The external air inlet hole 373 may be additionally formed in theinclined external wall 361 a of the narrow region 381. The external airinlet hole 373 is formed in a direction, which intersects the rotationaldirection of the rotor, not only in the wide region 382 but also thenarrow region 381 so that external air can be sucked into the rotor atthe same velocity of flow without getting bent.

As another alternative embodiment even though not illustrated, theexternal air 361 may be formed continuous in circumferential directionand the internal wall may be formed discontinuous. In other words, theinternal wall 363 may be intermittent or bent. The structure of theinternal wall may be equal to that of the external wall described in theillustrated embodiment above. To put it plainly, the radial-directioninside and outside of the air inlet part 341 or the external inletchannel 365 shown in FIG. 13 are reversed. In other words, not theradial-direction outside but the radial-direction inside is saw-toothed.

As a further alternative embodiment not illustrated, both of theexternal and external walls 361 and 363 may be intermittent or bent inthe radial direction. To put it plainly, both of the radial-directioninside and outside of the air inlet part 341 or the external air inletchannel 365 shown in FIG. 13 may be saw-toothed.

At this time, the internal external walls include radial-direction wallswhich face each other in the narrow region 381 in a circumferentialdirection and which are bent in the wide region 382 in the oppositedirection. The radial-direction inner saw-teeth and the radial outersaw-teeth have the same center in a circumferential direction.

The external air supply channel 365 mentioned above may providefollowing effects.

The external air supply channel 365 is able to perform the function ofcollecting external air flow from the external bottom surface of therotor frame 320 along the circumferential direction. In other words, airnear the outer bottom surface of the rotor frame is collected in theexternal air supply channel 365 along the rotation of the rotor frame320.

Especially, air near the center of the rotor frame flows in an outerradial direction to be collected in the external air supply channel 365.The air flowing along the external air supply channel 365 is guidedtoward the external air inlet hole 373 and drawn into the rotor.

Accordingly, external air may be sucked into the rotor very effectivelyand smoothly and the heat inside the rotor may be exhausted outside veryeffectively and efficiently.

FIG. 14 is a diagram illustrating one example modified from theembodiment shown in FIG. 13.

The illustrated example is characterized in that the external air inletchannel is formed in a spiral shape. The air rotated in thecircumferential direction in the external air supply channel flows tothe outer portion with respect to the radial direction and to theexternal air inlet channel. At this time, air flow resistance may begenerated. Accordingly, the external air inlet channel is formed in thespiral shape and the air flow resistance may be reduced.

In this instance, an outer surface and a front surface of the externalair inlet channel are connected with each other so as to form auni-curved surface. Accordingly, the flow direction of air may not bechanged suddenly but be guided smoothly into the rotor.

Moreover, the outer surface and the front surface may function asblades, so that air flow outside the rotor frame can be facilitated moresmoothly by the blades. Accordingly, the air can be sucked into therotor frame more effectively.

The rotor frame is made by pressing in the embodiments mentioned above.In other words, the entire rotor frame may be made of one material asone body. A level steel plate is pressed, bent and cut to integrallyform the side wall, the hub and the air inlet parts as one body.

In the structure of the air inlet part which is different from what isdescribed above, the side walls are not bent perpendicularly andconsecutively. The side walls are perpendicular to each other andcorners are rounded to be consecutive.

Different from the steel plate pressing, the rotor frame may be formedby dye casting. In this instance, it may be possible to form the complexshape of the air inlet part more precisely.

Even when all of the components which consist of the embodiments arecombined with each other as one body, the present disclosure is notnecessarily limited to the embodiments described above. The foregoingembodiments are merely exemplary and are not to be considered aslimiting the present disclosure.

The present teachings can be readily applied to other types of methodsand apparatuses. This description is intended to be illustrative, andnot to limit the scope of the claims. Many alternatives, modifications,and variations will be apparent to those skilled in the art. Thefeatures, structures, methods, and other characteristics of theexemplary embodiments described herein may be combined in various waysto obtain additional and/or alternative exemplary embodiments. As thepresent features may be embodied in several forms without departing fromthe characteristics thereof, it should also be understood that theabove-described embodiments are not limited by any of the details of theforegoing description, unless otherwise specified, but rather should beconsidered broadly within its scope as defined in the appended claims,and therefore all changes and modifications that fall within the metesand bounds of the claims, or equivalents of such metes and bounds, aretherefore intended to be embraced by the appended claims.

The following is an embodiments list.

1. A twin laundry machine comprising: a first washing unit comprising afirst tub, a first drum and a first drive unit for driving the firstdrum; a second washing unit comprising a second tub, a second drum and asecond drive unit for driving the second drum,

wherein the second drum has a diameter which is larger than the heightand a rotation axis which intersects a rotation axis of the first drum,

the second drive unit comprises a stator fixed to an outer surface of abottom wall of the second tub; a drum shaft connected to the seconddrum, penetrating the second tub; and a rotor coupled to the drum shaftand rotatably surrounding the stator, and

the rotor comprises a rotor frame; a magnet; and a connector forconnecting the rotor frame and the drum shaft with each other, and

the rotor frame comprises a side wall in which the magnet is mounted; abottom wall horizontally extended from a lower end of the side wall; andan air inlet part formed in the bottom wall, and

the air inlet part comprises,

a first wall projected toward the stator and formed in a circumferentialdirection to face a side wall of the rotor;

a second wall projected toward the stator from an inner portion of therotor side wall in a radial direction with respect to the first wall andalternate with the first wall in a circumferential direction;

a third wall projected in a circumferential direction from an innerportion of the rotor side wall in a radial direction with respect to thesecond wall to face the first wall and the second wall; and

a plurality of side walls for connecting the first wall and the secondwall with each other, and

the side wall comprises a first side wall for connecting one end of thefirst wall and one end of the neighboring second wall with each other;and a second side wall for connecting the other end of the first walland one end of the neighboring second wall, and

an opening in which air is sucked into the rotor frame is formed in thefirst side wall.

2. The twin laundry machine of embodiment 1, wherein the second washingunit is separable from the first washing unit.

3. The twin laundry machine of embodiment 1, wherein the second tub andthe second drum are vertically arranged in the second washing unit.

4. The twin laundry machine of embodiment 3, wherein the second washingunit is arranged on a top of the first washing machine.

5. The twin laundry machine of embodiment 1, wherein the rotor comprisesa hub projected from a center of the bottom wall toward the drum shaftand comprising a horizontal surface opposite to the stator and avertical surface opposite to the drum shaft.

6. The twin laundry machine of embodiment 5, wherein the connector ismade of a plastic material and coupled to the drum shaft to be coupledto the rotor frame, in close contact with the horizontal surface and thevertical surface of the hub.

7. The twin laundry machine of embodiment 6, wherein the hub comprisesanother vertical surface opposite to the second wall of the air inletpart and projected toward the stator.

8. The twin laundry machine of embodiment 6, wherein the horizontalsurface of the hub is a bottom wall of the rotor near the third wall ofthe air inlet part.

9. The twin laundry machine of embodiment 1, wherein the second sidewall of the air inlet part forms a front side with respect to arotational direction of the rotor, and

the first side wall in which the opening is formed to suck air forms arear side with respect to the rotational direction of the rotor.

10. The twin laundry machine of embodiment 1, wherein an opening formedin a first side wall of the air inlet part is vertically formed withrespect to a bottom surface of the rotor.

11. The twin laundry machine of embodiment 1, wherein a second side wallof the air inlet part is longer than a first side wall in which theopening is formed.

12. The twin laundry machine of embodiment 1, wherein one side of thesecond wall of the air inlet part is closer to the side wall of therotor than the other side in a radial direction.

13. The twin laundry machine of embodiment 12, wherein a first side wallof the air inlet part is connected with one side of the second wallformed close to the side wall of the rotor in the radial direction.

14. The twin laundry machine of embodiment 12, wherein a predeterminedfront portion of the second wall of the air inlet part with respect tothe rotation direction of the rotor is closer to the side wall of therotor in the radial direction than the other rear portion.

15. The twin laundry machine of embodiment 1, wherein the second wall ofthe air inlet part further comprises an opening in which air is able tobe sucked.

16. A drive unit of a laundry machine comprising a tub; a drum mountedin the tub and configured to wash laundry; the drive unit connected to adrum shaft penetrating the tub and configured to drive the drum, thedrive unit comprising:

a stator fixed to an outer surface of a bottom wall provided in the tub;and

a rotor coupled to the drum shaft and supported to rotate, withsurrounding the stator,

wherein the rotor comprises,

a rotor frame; a magnet; and

a connector for connecting the rotor frame and the drum shaft with eachother, and

the rotor frame comprises,

a side wall for seating the magnet therein; and

a bottom wall horizontally extended from a lower end of the side wall,and

an external air supply channel is projected from the stator toward thestator in a circumferential direction to be recessed from an outersurface of the bottom wall continuously, and

the external air supply channel comprises,

an internal wall formed in a radial direction and an external wallformed in the radial direction;

an external wall formed outer to the internal wall in a radialdirection;

a narrow region having a relatively narrow width between the internalwall and the external wall; and

a wide region having a relatively wide width between the internal walland the external wall, and

an external air inlet hole is formed an internal or external wallportion of the wide region which faces one end of the narrow region.

17. The drive unit of the laundry machine of embodiment 16, wherein theinternal wall of the external air supply channel is continuously formedin a circumferential direction and the external wall is bending in thecircumferential direction.

18. The drive unit of the laundry machine of embodiment 17, wherein theexternal wall comprises,

a circumferential-direction wall facing the internal wall in the narrowregion and bending in a radial direction to intersect the internal wallin the wide region; and

a radial-direction wall bending in a radial direction in the wide regionto intersect the internal wall.

19. The drive unit of the laundry machine of embodiment 18, wherein theexternal air inlet hole is formed in one of the radial-direction wallsprovided in the external wall.

20. The drive unit of the laundry machine of embodiment 19, wherein theexternal air inlet hole is located in a rear one of the radial-directionwalls of the external wall with respect to the rotational direction ofthe rotor.

21. The drive unit of the laundry machine of embodiment 18, wherein thecircumferential-direction wall is inclined along the circumferentialdirection in the narrow region or the wide region.

22. The drive unit of the laundry machine of embodiment 21, wherein afront portion of the radial-direction wall is outer to a rear portion inthe narrow region in a radial direction with respect to the rotationaldirection of the rotor.

23. The drive unit of the laundry machine of embodiment 22, wherein theexternal air inlet hole is additionally formed in thecircumferential-direction wall in the narrow region.

24. The drive unit of the laundry machine of embodiment 18, wherein theradial-direction wall is bent perpendicular to the internal wall in thewide region.

25. The drive unit of the laundry machine of embodiment 16, wherein theexternal wall of the external air supply channel is continuously formedin a circumferential direction and the internal wall is bent in thecircumferential direction.

26. The drive unit of the laundry machine of embodiment 25, wherein theinternal wall comprises,

a radial-direction wall facing the external wall in the narrow region;

a radial-direction wall bent inward in a radial direction to intersectthe external wall in the wide region.

27. The drive unit of the laundry machine of embodiment 26, wherein theexternal air inlet hole is formed in one of the radial-direction wallsprovided in the internal wall.

28. The drive unit of the laundry machine of embodiment 27, wherein theexternal air inlet hole is located in a rear one of the radial-directionwalls of the internal wall with respect to the rotational direction ofthe rotor.

29. The drive unit of the laundry machine of embodiment 26, wherein thecircumferential-direction wall is inclined along the circumferentialdirection in the narrow region or the wide region.

30. The drive unit of the laundry machine of embodiment 29, wherein afront portion of the radial-direction wall is outer to a rear portion inthe narrow region in a radial direction with respect to the rotationaldirection of the rotor.

31. The drive unit of the laundry machine of embodiment 50, wherein theexternal air inlet hole is additionally formed in thecircumferential-direction wall in the narrow region.

32. The drive unit of the laundry machine of embodiment 24, wherein theradial-direction wall is bent perpendicular to the external wall in thewide region.

33. The drive unit of the laundry machine of embodiment 16, wherein theinternal wall and the external wall are bent in the circumferentialdirection.

34. The drive unit of the laundry machine of embodiment 33, wherein theinternal and external walls comprise circumferential-direction wallsfacing each other in the narrow region; and

Radial-direction walls bent in an opposite direction in the wide region.

35. The drive unit of the laundry machine of embodiment 34, wherein theexternal air inlet hole is formed in one of the radial-direction wallsin the wide region.

36. A laundry machine comprising:

a first washing unit comprising a first tub and a first motor fordriving the first tub;

a second washing unit comprising a second tub and a second motor fordriving the second tub;

a first controller for controlling the first washing unit; and

a second controller for controlling the second washing unit,

wherein the first controller categorizes operations of the first motorfor performing washing, rinsing and spinning cycles according tooperation settings by motion unit, and sets the time period in which thefirst motor performs one motion one time as one operation-on period andcontrols an operation-on period of the first motor and an operation-onperiod of the second motor not to be overlapped with each other.

37. The laundry machine of embodiment 36, wherein the first controllercontrols the first motor to perform the motion configured to give awashing effect to the laundry loaded in the tub by combining one or moreof the clockwise rotation, pausing, counter-clockwise rotation,high-velocity rotation and low-velocity rotation for the firstoperation-on period.

38. The laundry machine of embodiment 37, wherein the first controllercontrols the first motor by setting one of laundry entangling, laundrysoaking, detergent dissolving and laundry rubbing for giving a washingeffect to the laundry as the motion.

39. The laundry machine of embodiment 36, wherein the first motorrepeats power-on and power off predetermined times for the operation-onperiod, corresponding to the motion.

40. The laundry machine of embodiment 36, wherein the first motorcontinues the operation for the operation-on period, corresponding tothe motion.

41. The laundry machine of embodiment 36, wherein the first controllercontrols the operation-on period of the first motor and the operation-onperiod of the second motor not to be overlapped with each other byconstant communication with the second controller.

42. The laundry machine of embodiment 36, wherein the first controllercontrols the first motor to perform a first motion for a firstoperation-on period, and the second controller sets a firstoperation-off period for the second motor to standby for the firstoperation-on period.

43. The laundry machine of embodiment 42, wherein the second controllersets the first operation-off period which has the same size as the firstoperation-on period.

44. The laundry machine of embodiment 42, wherein the first controllercontrols the first motor to perform the first motion one time andcontrols the first motor to standby for a second operation-off periodwhen the first opening-on period ends, and the second controllercontrols the second motor to perform a second motion for a secondoperation-on period when the first operation-on period ends.

45. The laundry machine of embodiment 44, wherein the first controllersets the second operation-off period, corresponding to the secondoperation-on period of the second motor.

46. The laundry machine of embodiment 44, wherein the first controllersets the operation-off period for the first motion which is set in casethe first washing unit is operated alone to be different from the secondoperation-off period.

47. The laundry machine of embodiment 44, wherein the first controllercontrols the first motor to perform a third motion for a thirdoperation-on period when the second operation-on period ends, and

the second controller sets a third operation-off period for the secondmotor to standby for the third operation-on period.

48. The laundry machine of embodiment 44, wherein the first controllercontrols the first motor to perform the first motion one more time for afourth operation-on period when the second operation-on period ends, andthe second controller sets a fourth operation-off period for the secondmotor to standby for the fourth operation-on period.

49. The laundry machine of embodiment 47, wherein the first operation-onperiod, the second operation-on period and the third operation-on periodare different in size.

50. A control method of a laundry machine comprising a first washingunit comprising a first tub and a first motor for driving the first tub;a second washing unit comprising a second tub and a second motor fordriving the second tub, the control method comprises,

a step for controlling the first motor to perform a first motion of themotions implemented to give the laundry loaded in the first tub certainwashing effects for a first operation-on period;

a step for controlling the second motor to standby for a firstoperation-off, corresponding to the first operation-on period;

a step for controlling the second motor to perform a second motion ofthe motions for a second operation-on period, when the firstoperation-on period ends;

a step for controlling the first motor to standby for a secondoperation-off period, corresponding to the second operation-on period;and

a step for controlling the first motor and the second motor to performthe motions combined with the plurality of the operations foroperation-on periods which are set not to be overlapped with each other,respectively.

51. The control method of the laundry machine of embodiment 50, furthercomprising:

a step for setting each operation-on period and operation-off period forthe next motion for the operation-on periods of the first motor not tobe overlapped with the operation-on periods of the second motor bycommunication between the first controller of the first washing unit andthe second controller of the second washing unit, when one operation-onperiod of the first or second motor ends.

52. The control method of the laundry machine of embodiment 50, furthercomprising:

a step for controlling the first controller to set the time taken toperform the first motion one time as the first operation-on period,before the first motor performs the first motion; and

a step for controlling the second controller to set the firstoperation-off period for the second motor, corresponding to the firstoperation-on period.

53. The control method of the laundry machine of embodiment 51, furthercomprising:

a step for controlling the second controller to set the time taken toperform the second motion one time as the second operation-on periodbefore the second motor performs the second motion; and

a step for controlling the first controller to set the secondoperation-off period, corresponding to the second operation-on period.

54. The control method of the laundry machine of embodiment 50, whereinthe operation-on period for the first motion is set different from thesecond operation-off period, when the first washing unit is operatedalong.

55. The control method of the laundry machine of embodiment 50, whereinthe size of the operation-off period in which the second motor standbys,not operating, is set corresponding to the size of the operation-onperiod in which the first motor is being operated, and

the size of the operation-off period in which the first motor standbys,not operating, is set corresponding to the size of the operation-onperiod in which the second motor is being operated.

56. The control method of the laundry machine of embodiment 50, furthercomprising:

a step for controlling the first motor to perform a third motion for athird operation-on period, when the second operation-on period ends; and

a step for controlling the second motor to standby for a thirdoperation-off period which is set corresponding to the thirdoperation-on period.

57. The control method of the laundry machine of embodiment 50, furthercomprising:

a step for controlling the first motor to perform the first motion onemore time for a fourth operation-on period, when the second operation-onperiod ends; and

a step for controlling the second motor to standby for a fourthoperation-off period which is set in the second motor, corresponding tothe fourth operation-on period.

58. The control method of the laundry machine of embodiment 56, whereinthe first operation-on period, the second operation-on period and thethird operation-on period are different in size.

59. The control method of the laundry machine of embodiment 50, whereinthe motion is set to give a washing effect to the laundry loaded in thetub by combining one or more of the clockwise rotation, pausing,counter-clockwise rotation, high-velocity rotation and low-velocityrotation for the first operation-on period.

What is claimed is:
 1. A twin laundry machine comprising: a firstwashing unit comprising a first tub, a first drum mounted in the firsttub, and a first drive unit that penetrates the first tub and that isconfigured to drive a rotation of the first drum within the first tub;and a second washing unit comprising a second tub, a second drum mountedin the second tub, and a second drive unit that penetrates the secondtub and that is configured to drive a rotation of the second drum withinthe second tub, wherein the second drive unit comprises: a stator fixedto an outer surface of a wall of the second tub; a drum shaft that isconnected to the second drum and that penetrates the second tub; and arotor coupled to the drum shaft and rotatably surrounding the stator,the rotor comprising a rotor frame connected to the drum shaft, and amagnet, the rotor frame comprising: a side frame portion configured tomount the magnet of the rotor; and a base frame portion extending from afirst end of the side frame portion, the base frame portion comprising aplurality of external air inlet channels projecting from a surface ofthe base frame portion toward the stator, each of the plurality ofexternal air inlet channels comprising: a first wall projecting from thesurface of the base frame portion toward the stator and extending alonga circumferential direction of the rotor frame at a first radialdistance from a radial center of the base frame portion; a second wallextending from a projecting end of the first wall toward the radialcenter of the base frame portion; a third wall projecting from thesurface of the base frame portion toward the stator and extending alongthe circumferential direction of the rotor frame at a second radialdistance smaller than the first radial distance from a radial center ofthe base frame portion; and a fourth wall projecting from the surface ofthe base frame portion to the second wall and extending from the firstwall to the third wall, wherein the first wall, the second wall, thethird wall and the surface of the base frame portion define an openingof each of the plurality of external air inlet channels, the openingbeing configured to, in a state in which the rotor frame rotates, drawexternal air guided by each of the plurality of external air inletchannels into an interior of the rotor frame through the base frameportion, wherein the opening of each of the plurality of external airinlet channels is separated and spaced apart from the fourth wall of anadjacent external air inlet channel of the plurality of external airinlet channels that faces said opening, wherein the second wall of eachof the plurality of external air inlet channels is separated and spacedapart from the second wall of an adjacent external air inlet channel ofthe plurality of external air inlet channels, and wherein the third wallof each of the plurality of external air inlet channels is separated andspaced apart from the third wall of an adjacent external air inletchannel of the plurality of external air inlet channels.
 2. The twinlaundry machine of claim 1, wherein the second washing unit isconfigured to be separable from the first washing unit.
 3. The twinlaundry machine of claim 1, wherein the second washing unit is arrangedon a top portion of the first washing unit.
 4. The twin laundry machineof claim 1, wherein the rotor of the second drive unit furthercomprises: a connector configured to connect the rotor frame and thedrum shaft.
 5. The twin laundry machine of claim 4, wherein the rotor ofthe second drive unit of the second washing unit further comprises: ahub provided at the radial center of the base frame portion of the rotorframe of the second drive unit, wherein the connector of the rotor ofthe second drive unit is coupled to the drum shaft of the second driveunit to be coupled to the rotor frame of the second drive unit andfitted with the hub of the rotor.
 6. The twin laundry machine of claim5, wherein the connector of the rotor of the second drive unit iscomposed of a plastic material.
 7. The twin laundry machine of claim 5,wherein the hub projects from the radial center of the base frameportion of the rotor frame of the second drive unit toward the drumshaft of the second drive unit, and comprises a central surface oppositeto the stator of the second drive unit and a first lateral surfaceopposite to the drum shaft of the second drive unit, the central surfacearranged perpendicular to the drum shaft.
 8. The twin laundry machine ofclaim 7, wherein the hub of the rotor of the second drive unit comprisesa second lateral surface that is concentric with the first wall of eachof the plurality of external air inlet channels and projected toward thestator.
 9. The twin laundry machine of claim 7, wherein the centralsurface of the hub of the rotor of the second drive unit is a baseportion of the rotor surrounding the drum shaft of the second driveunit.
 10. The twin laundry machine of claim 1, wherein each of theplurality of external air inlet channels projects from the surface ofthe base frame portion toward the stator such that the opening of eachof the plurality of external air inlet channels extends in a depth-wisedirection of the drum shaft from the surface of the base frame portionof the rotor of the second drive unit.
 11. The twin laundry machine ofclaim 1, wherein: at least a portion of the first wall of each of theplurality of external air inlet channels extends in a depth-wisedirection of the drum shaft from the surface of the base frame portionof the rotor, and at least a portion of the second wall of each of theplurality of external air inlet channels extends in a breadth-wisedirection of the surface of the base frame portion of the rotor.
 12. Thetwin laundry machine of claim 1, wherein the plurality of external airinlet channels comprise a first air inlet channel, and wherein the firstwall, the second wall, and the surface of the base frame portion definethe opening of the first air inlet channel by: the first wall defining afirst boundary of the opening of the first air inlet channel andextending in a depth-wise direction of the drum shaft from the surfaceof the base frame portion of the rotor; the second wall defining asecond boundary of the opening of the first air inlet channel andextending in a breadth-wise direction of the surface of the base frameportion of the rotor; and the surface of the base frame portion of therotor defining a third boundary of the opening of the first air inletchannel and extending in the breadth-wise direction of the surface ofthe base frame portion of the rotor.
 13. The twin laundry machine ofclaim 1, wherein the second wall of each of the plurality of externalair inlet channels extends from the projecting end of the first wall ofeach of the plurality of external air inlet channels to a projecting endof the third wall of each of the plurality of external air inletchannels in a radial direction of the rotor frame.
 14. The twin laundrymachine of claim 1, wherein the plurality of external air inlet channelsis configured to: in a state in which the rotor frame rotates in a firstcircumferential direction, draw the external air upward through the baseframe portion via the opening of each of the plurality of external airinlet channels and into the rotor frame flowing in a secondcircumferential direction that is opposite the first circumferentialdirection.